Composite circular connector seal and method of use

ABSTRACT

A composite circular connector seal, or an assembly comprising a plurality of such seals, may be engineered to seal across a predetermined tolerance band for such seals by using two substantially circular seal elements sized to slidingly fit about a tubular that has a positive and negative outer diameter tolerance range, where each seal element is terminated at one circumferential edge with a packer cap, and a core element disposed intermediate the two substantially circular seal elements at their respective non-packer cap terminated circumferential edges. The two substantially circular seal elements comprise an organic thermoplastic polymer and the core seal element, which typically comprises a synthetic rubber, is also typically molded to the two seal elements at their respective non-packer cap terminated circumferential edges.

RELATION TO PRIOR APPLICATIONS

This application claims the benefit of, and priority through, U.S. Provisional Application 62/146,698, titled “Capping Stack Hydraulic Slip-On Connector Seal Assembly,” filed Apr. 13, 2015.

BACKGROUND

Sealing performance is critical for success in certain subsea operations, including cap and contain deepwater well control. Current seals require that a specific seal be used for a series of sizes or, alternatively, to use multiple seals as opposed to a single stack.

FIGURES

Various figures are included herein which illustrate aspects of embodiments of the disclosed invention.

FIG. 1 is a cutaway view in partial perspective of an exemplary seal;

FIG. 2 is a view in partial perspective of an exemplary seal;

FIG. 3 are two views in partial perspective of an exemplary seal assembly; and

FIG. 4 is a cutaway view in partial perspective of an exemplary seal deployed in a housing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Generally, as described below composite circular connector seals 1 (FIG. 1) are typically engineered to seal across a predetermined tolerance band for seals such as one specified for API Spec 5CT casing, i.e. +1% to −0.5% on the outside diameter. This can help avoid the need and cost of maintaining an inventory of multiple seal packs (for example, one for the high side of the casing tolerance and another for the low side) and also the operational complexity of having to install the appropriate seal pack in the field.

Referring now to FIG. 1, in a first embodiment composite circular connector seal 1 defines a fully circumferential composite seal and is configured to lock and seal over tubular 100 (FIG. 3). Composite circular connector seal 1 comprises an outer diameter “D” (FIG. 2) sized to slidingly fit about tubular 100, where tubular 100 comprises a positive and negative outer diameter tolerance range. As used herein, a “tubular” may be a riser, a vertical flow casing, a conduit, or the like, most typically for subsea use.

Composite circular connector seal 1 comprises a composite stack which comprises two substantially circular seal elements 12 and a substantially circular core seal element 10 disposed intermediate to, typically molded to, the two seal elements 12. Each seal element 12 is typically configured to seal about tubular 100 to a predetermined sealing percentage and is typically used as a primary seal anti-extrusion mechanism.

In certain embodiments, each seal element 12 comprises an organic thermoplastic polymer and each is terminated at the non-molded circumferential edge with packer cap 14, which, in preferred embodiments, comprises packer caps comprising Inconel and which may further comprise a fixed diameter. The organic thermoplastic polymer may comprise a polyether ether ketone (PEEK) which, as core seal element 10 is compressed, moves into seal gap 103 (FIG. 4) to create a barrier to contain core seal element 10 material.

Referring additionally to FIG. 4, core seal element 10 typically comprises a synthetic rubber, such as nitrile rubber (NBR). Typically, as the two seal elements 12 are compressed, the organic thermoplastic polymer, e.g., PEEK, moves into seal gap 103 to create a barrier to contain core seal element 10. As further illustrated in FIG. 4, core seal element 10 is typically configured such that under longitudinal compressive load of composite circular connector seal 1 (FIG. 1) core seal element 10 flows into seal gap 103 between outside 101 of tubular 100 and an inside 111 of housing 110 to create a positive seal. As used herein, a housing can be another tubular, a wellbore, or another structure, or the like. By way of example and not limitation, this positive seal may be a positive seal on an API 5CT casing across a range of minimum and maximum outer diameter tolerances for tubular 100. In certain embodiments, composite circular connector seal 1 is configured to create a positive seal load maintained on tubular 100 equal to or greater than 1.2 times the maximum allowable operating pressure (MAOP) of tubular 100. As also illustrated in FIG. 4, the volume of core seal element 10 may remain constant but its shape may alter to match the volume fill during sealing.

In its various embodiments, the flow of both the core seal element 10 material and the seal element 12 material move the inner and outer diameters of packer cap 14 to the limit of seal gap 103, creating a near metal-to-metal seal on the front and back of the core seal element 10 material and the seal element 12 material. In most embodiments, this prevents extrusive flow of either the core seal element 10 material or the seal element 12 material from either end of composite circular connector seal 12 during full compressive load and operating pressure in tubular 10.

Referring now to FIG. 3, in an embodiment slip-on connector seal assembly 50 comprises two composite circular connector seals 1, e.g. first composite circular connector seal 1 a and second composite circular connector seal 1 b, and metal ring 20, sometimes referred to as a Lantern Ring, disposed intermediate first composite circular connector seal 1 a and second composite circular connector seal 1 b. These two composite circular connector seals 1 are as described above.

In the operation of exemplary embodiments, composite circular connector seals 1 and/or slip-on connector seal assembly 50 have the capacity to seal over a substantially complete range of outer diameter tolerances for such seals. By way of example and not limitation, in certain embodiments one or more slip-on connector seal assemblies 50 and/or composite circular connector seals 1 may be used as a slip-on riser end connector for an out-of-control riser blowout preventor (BOP) situation. In those embodiments, one or more slip-on connector seal assemblies 50 and/or composite circular connector seals 1 may be attached below a BOP capping stack and lowered onto a free flowing riser in the event of an uncontrollable blowout condition. Once installed onto the free flowing riser, these one or more slip-on connector seal assemblies 50 and/or composite circular connector seals 1 may then be mechanically attached and sealed to the outer diameter of the tubular.

Referring generally to FIGS. 3 and 4, one or more slip-on connector seal assemblies 50 and/or composite circular connector seals 1 is disposed over a tubular, conduit, casing, or the like such as tubular 100 and positioned in-between outside 101 of tubular 100 and inside 111 of housing 110. Tubular 100 may have one or more deflections, shown in FIG. 4 as bulge 102, as well as positive and negative outer diameter tolerance ranges. When pressure is applied, core seal element 10 is deformed to contact outside 101 of tubular 100 and inside 111 of housing 110 at seal contact region 103.

One or more slip-on connector seal assemblies 50 and/or composite circular connector seals 1 may be locked and sealed onto tubular 100 by maneuvering the one or more slip-on connector seal assemblies 50 and/or composite circular connector seals 1, as described above, to a predetermined position on tubular 100 where composite circular connector seal 1 is installed and configured to lock and seal over tubular 100.

Once installed onto tubular 100, one or more of positioned composite circular connector seals 1 are mechanically attached, locking onto tubular 100 and being sealed onto outer diameter 101 of tubular 100.

If two composite circular connector seals 1 are used, e.g. if one or more slip-on connector seal assemblies 50 is used, the second composite circular connector seal 1 b (FIG. 3) may be maneuvered to a second predetermined position on tubular 100 proximate the first composite circular connector seal 1 a (FIG. 2), either separately or as part of slip-on connector seal assembly 50, and a reduced test pressure applied between two composite circular connector seals 1 a, 1 b to validate that a positive seal has been obtained prior to applying a full maximum allowable operating pressure to tubular 100. Typically, as described above, two composite circular connector seals 1 are separated by metal ring 20.

If synthetic rubber and PEEK materials are used, a flow of both the synthetic rubber and PEEK materials may be allowed to move the inner diameter and outer diameter of packer cap 14 to the limit of seal gap 103, thus creating a near metal-to-metal seal on the front and back of the synthetic rubber/PEEK core of composite circular connector seal 1 to prevent extrusive flow of either the synthetic rubber or PEEK materials from either end of composite circular connector seal assembly 50 during full compressive load and operating pressure in tubular 100. Additionally, for such embodiments, each seal element 12 that is molded to the synthetic rubber may be used as the primary seal anti-extrusion mechanism such that as the synthetic rubber seal is compressed, the PEEK element moves into seal gap 103 to create a barrier to contain the synthetic rubber. As will thus be apparent to one of ordinary skill in the sealing arts, under longitudinal compressive load of the connector, core seal element 10 flows into seal gap 103 to create a positive seal and, typically, its volume remains constant but its shape is altered to match the volume fill.

Additionally, composite circular connector seal 1 may be used to create a positive seal on API 5CT casing across a range of minimum and maximum outer diameter tolerances. In certain embodiments composite circular connector seal 1 is used to create a positive seal load maintained on the casing equal to or greater than 1.2 times the maximum allowable operating pressure (MAOP) of tubular 100 which, as noted before, may be a vertical free flowing casing.

In certain embodiments, core seal element 10 is allowed to flow into seal gap 103 to create a positive seal under longitudinal compressive load of composite circular connector seal 1. The volume of core seal element 10 may be maintained at a constant value and a shape of core seal element 10 may be altered to match the volume filled by core seal element 10 during sealing.

The foregoing disclosure and description of the inventions are illustrative and explanatory. Various changes in the size, shape, and materials, as well as in the details of the illustrative construction and/or an illustrative method may be made without departing from the spirit of the invention. 

1. A composite circular connector seal, comprising a composite stack, the composite stack comprising: a. two substantially circular seal elements, each seal element comprising an outer diameter (D) sized to slidingly fit about a tubular, the tubular comprising a positive and negative outer diameter tolerance range, and an organic thermoplastic polymer, each seal element terminated at one circumferential edge with a packer cap ; and b. a core seal element comprising an outer diameter substantially the same as the outer diameter of the two substantially circular seal elements, the core seal element disposed intermediate to the two seal elements at their respective non-packer cap terminated circumferential edges.
 2. The composite circular connector seal of claim 1, wherein the core seal element is molded to the two seal elements at their respective non-packer cap terminated circumferential edges.
 3. The composite circular connector seal of claim 1, wherein the packer caps comprise Inconel.
 4. The composite circular connector seal of claim 1, wherein the packing caps comprise a fixed diameter substantially the same as the outer diameter of the two substantially circular seal elements.
 5. The composite circular connector seal of claim 1, wherein the organic thermoplastic polymer comprises a polyether ether ketone (PEEK).
 6. The composite circular connector seal of claim 5, wherein the PEEK seal element is configured to seal about the tubular to a predetermined sealing percentage.
 7. The composite circular connector seal of claim 1, wherein the core seal element comprises a synthetic rubber.
 8. The composite circular connector seal of claim 7, wherein: a. the composite circular connector seal is contained in a mechanical compressor operative to compress the composite circular connector seal onto a tubular; and b. the core seal element is configured such that under longitudinal compressive load of the mechanical compressor the core seal element deforms to fill a seal gap between an outside of the tubular and an inside of a housing to create a positive seal.
 9. The composite circular connector seal of claim 7, wherein the seal element that is molded to the synthetic rubber core seal element is the primary seal anti-extrusion mechanism and configured such that as the synthetic rubber seal is compressed, the organic thermoplastic polymer deforms to fill the seal gap and create a barrier to contain the synthetic rubber.
 10. The composite circular connector seal of claim 7, wherein the composite circular connector seal is configured to create a positive seal on the outside diameter of an API compliant tubular across a range of minimum and maximum tubular outer diameter tolerances.
 11. The composite circular connector seal of claim 10, wherein the composite circular connector seal is configured to create a positive seal contract pressure on the API compliant tubular equal to or greater than 1.2 times the maximum allowable operating pressure (MAOP) of the API compliant tubular.
 12. A composite seal assembly, comprising: a. a first composite circular connector seal and a second composite circular connector seal, each composite circular connector seal comprising a composite stack, each composite stack comprising: i. two substantially circular seal elements, each seal element comprising an outer diameter (D) sized to slidingly fit about a tubular, the tubular comprising a positive and negative outer diameter tolerance range, and an organic thermoplastic polymer, each seal element terminated at one circumferential edge with a packer cap ; and ii. a core seal element comprising an outer diameter substantially the same as the outer diameter of the two substantially circular seal elements, the core seal element disposed intermediate to the two seal elements at their respective non-packer cap terminated circumferential edges; and b. a metal ring disposed intermediate the first composite circular connector seal and the second composite circular connector seal.
 13. A method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range, comprising: a. maneuvering a first composite circular connector seal to a predetermined position about a tubular, the tubular comprising a positive and negative outer diameter tolerance range, the composite circular connector seal configured to lock and seal over the tubular, the first composite circular connector seal comprising a composite stack, the composite stack comprising: i. two substantially circular seal elements, each seal element comprising an outer diameter (D) sized to slidingly fit about a tubular, the tubular comprising a positive and negative outer diameter tolerance range, and an organic thermoplastic polymer, each seal element terminated at one circumferential edge with a packer cap ; and ii. a core seal element comprising an outer diameter substantially the same as the outer diameter of the two substantially circular seal elements, the core seal element disposed intermediate to the two seal elements at their respective non-packer cap terminated circumferential edges; and b. once installed onto the tubular, mechanically attaching, locking, and sealing the composite circular connector seal in-between an outside of the tubular and an inside of a housing into which the tubular is disposed.
 14. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 13, further comprising: a. maneuvering a second composite circular connector seal, the second composite circular connector seal substantially identical to the first composite circular connector seal, to a second predetermined position on the tubular proximate the first composite circular connector seal; and b. applying a reduced test pressure between two composite circular connector seals to validate a positive seal has been obtained prior to applying a full maximum allowable operating pressure to the tubular.
 15. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 13, further comprising allowing a flow of both the organic thermoplastic polymer and the synthetic rubber to move inner and outer diameters of the packer cap to a limit of the seal gap, creating a near metal-to-metal seal on the front and back of the organic thermoplastic polymer and the synthetic rubber to prevent extrusive flow of either of the organic thermoplastic polymer and the synthetic rubber from either end of the seal assembly during full compressive load and operating pressure in the tubular.
 16. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 13, further comprising allowing the organic thermoplastic polymer and/or the synthetic rubber to flow into an seal gap between a connector inner diameter and an outer diameter of the tubular to create a positive seal under longitudinal compressive load of the connector.
 17. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 16, further comprising: a. maintaining core seal element volume at a constant value; and b. altering a shape of the core seal element to match the core seal element volume fill during sealing.
 18. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 13, further comprising using the seal element that is molded to the synthetic rubber as the primary seal anti-extrusion mechanism such that as the synthetic rubber is compressed, the organic thermoplastic polymer moves into the seal gap to create a barrier to contain the synthetic rubber.
 19. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 13, further comprising configuring the composite circular connector seal to create a positive seal on API 5CT casing across a range of minimum and maximum OD tolerances.
 20. The method of providing a lock and seal onto a tubular with a positive and negative outer diameter tolerance range of claim 13, further comprising configuring the composite circular connector seal to create a positive seal load maintained on the casing equal to or greater than 1.2 times the maximum allowable operating pressure (MAOP) of the vertical free flowing casing. 